Equalizer for mechanically operated automobile brakes



Nov. 28, 1939. I D. NICQL, JR

EQUALIZER FOR MECHANICALLY OPERATED AUTOMOBILE BRAKES Z-She etS-Sheet 2' Filed March 15, 1939 &

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ATTD RNEYE Patented Nov. 28, 1939 PATENT OFFICE EQUALIZER FOR MECHANICALLY OPER- ATED AUTOMOBILE BRAKES David Nicol, nu, Willowdale, Ontario, Canada Application March 15, 1939, Serial No. 261,907

1 Claim.

My invention relates to improvements in equalizers for mechanically operated automobile brakes and the object of the invention is to automatically carry all the brake shoes to the braking position before applying the braking pressure, when any of such shoes are removed from the braking position either due to different amounts of slack in the connections between the brake pedal and shoes or due to different amounts of wear in the wearing surface of the brake shoes, and it consists essentially in the arrangement and construction of parts as hereafter explained.

Fig. 1 is a perspective view of my device.

Fig. 2 is a longitudinal sectional view through Fig. 1.

pedal.

Figs. 9'and 10 are sectional details on lines 9-9 and Ill-l Fig. 6.

In the drawings like characters of reference indicate corresponding parts.

and 2 are the side walls of a rectangular casing provided with upper and lower opposing guide ribs 3 and 4 secured thereto or formed integral therewith and forming upper, lower and intermediate guide Ways. 5 and B are the end walls.

The end wall 5 is provided with upper orifices 1 and 8 and lower orifices 9 and I0 and the'end wall 6 with a central orifice II.

A cross bar |2 is slidably held between the guide ribs 3 and 4. A plate I3 secured at one end to the'upper face of the cross bar I2, is slidable between the guide ribs 3 and a plate l4, secured at one end to the lower face of the cross bar I2,

is slidable between the guide ribs 4.

A pull rod l5 extends from the cross bar I through the orifice H and is pivotally connected at its outer end to the brake pedal l6. (See Fig. 8.)

Between the plates l3 and M is journalled a gear IT on a pin i8. Rack bars I9 and are slidably held between the guide ribs 3 and 4 at each side of the casing I so as vto mesh with the gear 2| and 22 are slide pieces slidable respectively between the upper bars 3 and the lower bars 4 and provided with lateral extensions 23 and 24. The rear end of the rack bar is reduced at l9 and secured to the extension 23 and. the rear end of the .arrow.

The plate 25 is secured to the slide piece 2| and the plate '26 to the slide piece 22. l 21-is a cylindrical stud extending from the plate 25 and 28 is a cylindrical stud extending-from the plate with the pin l8.

On the stud 2'! is revolubly mounted a gear 29 and on the stud 23 a gear 3|). Rack bars 3| and '32 are slidable on the guide ribs 3 so as to mesh '26. The studs 21 and 28 are in vertical alignment with each side of the gear 29. Rack bars 33 and I 34 are slidably mounted beneaththe guide ribs 4 so as to mesh with each side of the gear 30.

Pull rods 35 and 36 extend respectivelyfrom the rack bars 32 and 3| through the orifices and 8 of the casingand pull rods 3'!v and38 extend respectively from the rack bars 34 and 33 through the orifices 9 and ll] of the casing I.

The rods 31 and 38 are pivotally connected to the upper ends of the levers 39 and 40 which are 'pivotally mounted at 4| and '42 to any suitable supporting structure.

The lower ends of the levers 39 and 40 are connected by chains 43 and 44 passing over pulleys 45 and 48 to the front brake shoes 41 and 48 coacting with the brake drums 45 and 46 The pull rods 35 and 35 are connected by chains 49 and 581to the rear brake shoes 5| and 52 coacting with the brake drums 5| and 52 1 In the operation of the device it is assumed that there is more slack in the connection 49 to the brake shoe 5| than in the connection 5|], 44 and 43 and the operation will be as follows: I

The pedal I6 is pressed forward in the usua manner pulling the rod |5 in the direction of (See Fig. 8.) f Thepull on'the rod l5 draws the gear l1 and the rack bars l9 and 20 equally ina forward direction' such direction being indicated by arrow in Fig. 8.

By the forward movement of the rack bars l9 and 20 the pieces 2| and 22 secured respectively to the rack bars l9 and 20, the plates 25 and 26 secured to the pieces 2| and 22, the studs 21 and 28 carried respectivelyby the plates 25 and 26,

the gears 29 and38 journalled respectively on the studs 27 and 28, the racks 3| and 32 meshing with opposite sides of the gear 29, the racks 33 and 34 meshing with opposite sides of the gear 35. the rods 35 and 36 formed respectively integral with the'racks 3| and 32 and the rods 31 and. 38 formed respectively integral with the racks 33 and 34 are carried forward in unison until one or more of the brake shoes 41, 48, 5|

and 52 engage a coacting brake drum preventing further movement of those rods 35, 35, 31 and 38 which are connected to the engaged shoes.

In this illustration of the operation the rod is connected by the slack connection 49 to the brake shoe 5|. As soon as the remaining shoes 4?, 48 and 52 are drawn into contact with the drums 35 and 52 the racks 3|, 33 and 34 are held stationary from further forward movement. The racks 33 and 34 being station'- ary, the gear 30, stud 28, plate 26 and piece 22 are also held stationary holding the rack 23 stationary.

The pull on the rod l5 extending through the 7 cross bar l2, plates l3 and Hi to the pin l8 causes the gear IT to roll forward on the rack 20 so that the rack 59 geared tothe opposite side of the gear H is further carried forward.

The rack bar 59 being connected by the extension |9 to the cross piece 2| causes such rack bar it and cross piece 2| to move further forward carrying with them the plates 25 stud 21 and gear 23. This operation causes the gear 29 to roll on the stationarily held rack 3|, moving the rack 32 meshing with the opposite side of the gear 23 further forward pulling the rod 35 which is integral therewith also further forward to take up whatever slack there is in the connection 49.

If both connection 49 and are slack the operation is similar. In this case, however, both connection 49 and 53 being slack neither racks 3| and 32 are held stationary and therefore there is no rolling action of the gear 23 on either of these racks. As the gear 23 is moved forward Without rotation it draws both racks 3| and 32 forward to tighten the connections 43 and 53 drawing the shoes 5| and 52 into contact with the brake drums 5| and 52 Similarly, if the connections 43 and 36 are the slack connections, all the connections 53, 44, 49 and are drawn upon initially to first draw the brake shoes 5| and 52 into contact with their brake drums and then the remaining slack is taken up in the connections 43 and 44 by the gear I! rolling on the rack I3 to carry the rack 29 crosspiece 22, plate 23, stud 23, gear 33 and rack bars 33 and 34 forward.

The rods 35 and 36 being held from further movement by the contact of the brake shoes 5| and 52 with the drums 5| and 52 the gear 29 is held stationary together with the plate 25, the piece 2| secured to the plate 25 being also held stationary together with the rack l9 secured thereto. The gear N then rolls on the rack I3 moving the rack 23 forward together with the piece 22 which carries the stud 28, gear 33 and rack bars 33 and 34 also further forward to draw the connections 43 and 44 into tight braking contact.

If the connections 49 and 43 or the connections 50 and M are the slack connections the pull on the rod l5 draws the gear ll forward carrying the racks i9 23 in the same direction together with the pieces 2| and 22 to carry the plates 25 and 25 and the gears 29 and 30 mounted thereon forward and thereby carry the racks 3|, 32, 33, 34 forward until the shoes 5| and 41 or 52 and 48 contact with their respective brake drums. The gears 29 and 35 then roll on the racks 3| and 33 or racks 32 and 34 to carry further forward the opposing racks 32 and 34 or 3| and 33 to take up the slack in the connections 49 and 50 r or 43 and 44.

Actual demonstration has shown that when the brake drums are well greased there Will be no braking effect produced by the drawing of the brake shoes having the slack connections into contact with the drums prior to the take up of the slack in the slack connection and all the shoes carried into contact to simultaneously produce the braking action.

In order to vary the pressure exerted on the front and rear brake shoes the point of connection between the chains 53 and 44 and the levers 33 and 43 may be varied as indicated in Fig. 8 of the drawings.

What I claim as my invention is:

In an equalizer for mechanically operated automobile brakes, the combination with the front and rear brake shoes and the brake pedal, of a casing located between the front and rear shoes and having opposing upper and lower guide ways and opposing intermediate guide ways, a rack bar slidable in each upper guide way, a rack bar slidable in each lower guide way, a plate slidably mounted between the guides forming the upper guide. way, a plate slidably mounted between the guides forming the lower guide way, a gear rotatably mounted on each plate and meshing with the upper and lower racks, a connection between each upper rack and corresponding rear brake shoe, a connection between each lower rack and the corresponding front brake shoe, and means operated by the brake pedal for moving forward the plate connected to the shoes which have to be adjusted to the equalizing position while the other plate remains stationary when the corresponding shoes assume their braking position, such means comprising opposing rack bars slidable in the intermediate guide way of the casing, means for connecting one rack bar to the upper slide plate and the other rack bar to the lower slide plate, a member slidably mounted on the intermediate guide way and connected to the brake pedal, and a gear rotatably mounted on the intermediate slide member and meshing with the intermediate racks.

DAVID NICOL, JR. 

